def read_conductor_credentials(): ''' Read the conductor credentials file, if it exists. This will contain a bearer token from either the user or the API key (if that's desired). If the credentials file doesn't exist, try and fetch a new one in the API key scenario or prompt the user to log in. Args: use_api_key: Whether or not to use the API key

Returns: A Bearer token in the event of a success or None if things couldn't get figured out